Humidity control device



July- 27, H. J. KAUFMAN HUMIDITY CONTROL DEVICE Filed April 24, 1940 INVENTOR.

Patented July 27 19:43;

UNITED STATES l PATENT OFFICE j 2,325,061 HUMIDITY CONTROL DEVICE v Hiram Joseph Kaufman, Detroit, Mich.

, Application April 24, 1940, Serial No. 331,372 4 Claims. (01. 236-44) This invention relates to a humidity control device which uses a hygroscopic solution in combination with temperature to control relative humidity in connection with air conditioning apparatus. 5

One object of the invention is to provide a means for using the density of a hygroscopic solution, having a'vapcr pressure equal to that of the air in contact therewith, combined with a compensating thermostatic element to control the relative humidity of air at, variable tempera--- tures.

Another object of the invention is to provide a means for controlling relative humidity ,that is not afiected by freezing temperatures. I

A further object of the invention is to provide a hygroscopic element that may be continuously renewed and which can be easily and cheaply changed in ordertto remove impurities which may be absorbed from the air. I

This application is a continuation in part of my copending application Serial No. 294,584, filed September 13, 1939.

Referring to the drawing: I

Figure 1 is a diagram of an assembly of air 25 conditioning apparatus and the humidity control device to control therelative humidity of the air in a room.

Figure 2 is a plan section of the humidity control apparatus at the points marked (2-2).

Referring specifically to Figure 1; the case 10 encloses chemical dehumidifying apparatus comprisingithe cells ll, formed with wire cloth sides, tops and bottoms -I2 for holding granulatedor flake calcium chloride l3, separated by the air passages 14, supported by the rack l5 and all assembled within'the container I6, the cells H being filled with calcium chloride through i the door. 11. Underneath the said container areplaced the level pans l8 having th edges 19 turned up at an angle and the edge 2!! turned down at an-angle to form a drip. The calcium chloride is melted into a solution by means of moisture absorbed from the air and flows down I the porous sides I2 .01 the cells H and drips onto to the level pans I 8 which are horizontally spaced so that each pan has the same amount of surface exposed to the drippings of saturated or nearly saturated solution from the cells II. This solution on the pans l8 absorbs additional mois-.- ture from the air and becomes more liquid and is required to flow from the turned up edge l9- across the pans l8 and down over theturned down drip edge 20 into the lower portion of the case "I and out the drain pipe 2 I.

Air isdrawn by the fan 22 driven by the motor 23'into' the case I0 through the inlet 24 over and between the pans l8 in contact with and counter flow to that of the solution, then up- Ward through the air passages 14, in contact with the flake calcium chloride l3, and in counter flow to thatof the saturated or nearly saturated solution flowing down the porou sides I2 of the cells I I and of the air passages l4, through the space 25 and the damper 26 into the space 21,' or after passing between the pans I8, upward through the space 28, through the damper 29 and into the space 21,. from which it is discharged through the outlet 30. The dampers 26 and 29 are connected by the link 3i and the two ivots 32 and open and close alternately. The damper 26 is normally held closed and the damper 29 is normally held openby the coil spring 33. 4 The damper 26 is opened and the damper 23 is closed by the action of the damper motor 34 moving the damper motor arm 35 around the pivot 36, moving the bar 31 by means of the pivot 38, and the damper arm 39, attached to the damper 26, by means of the pivot 40.

The humidity control device comprises, in part, the case 50 having the partition 5|, the sloping floor 52 having the volute 53 for the pump impeller 54, the'gutters 55 and 58 and the splash screens 56, the latter composed of wire cloth.

The pump impeller 54 draws calcium chloride solution into the center of the volute 53 through the inlet 51 and is discharged from the blades of the pump impeller 54 against the splash screens 56-dripping into the gutter 58 and into the gutter 55. The pump impeller 54 is attached to the end of the shaft 59 which also carries and drives the fan 60, the shaft 59 being driven "62, which is attached to the case 50 and to the partition 51 The other part of the humidity control device comprises the hydrometer 63, floating in the calcium chloride solution which is held in the tube 64, and attached by the clamp 65, the bolt 66 and the pivot 61 to the lever 68. The opposite end of the lever 68 carries the mercury switch 69 and swings onthe pivot 10, whichis attached to the compensating thermostatic element 1| which slides up and down in the guides 12 which are attached by the bolts 13 to the standards 14. The height 01' the pivot 16 and the active length ofthe compensating thermostatic element 1! are regulated by the clamp 15 which is held in place by the set screw 16.,

Under some conditions, the waste solution flows from the chemical dehumidifying apparatus down the drain pipe 2|, through the pipe 11, the valve 18 being closed and'the valve I9 being opened, up through the tube 64,-wasting through the pipe 80, the valve 8| being opened,, and wasting away through the pipe 82. With a properly designed apparatus for dehumidifying air, the waste solution will have a vapor pressure in equilibrium with that of the air entering the inlet 24 and a corresponding sp cific gravity and temperature.

Under other conditions, the waste solution flows from the chemical dehumidifying apparatus down the drain pipe 2| and wastes away through the pipe 82, the valve I8 being opened and the valves I9 and BI being closed. The solution is recirculated by the pump impeller 54 through the gutters 58 and 55, the pipes 83 and I1, the tube 04', the pipe 84 and the pump inlet 51.

Air is drawn by the fan 60 through the inlet 86, into the case 50, downward through the space 81, thr'oughth'e opening 88, over the solution, upward over the splash screens 56, through the space 89 and discharged through the outlet 90. The solution, being hygroscopic, will attain equilibrium conditions of vapor pressure with that of the air in contact therewith and a corresponding specific gravity and temperature.

The vertical position of the clamp 15 on the standard I4 should be at a height where, with the hydrometer set at the proper level, the mercury in the tube of the switch 69 begins to flow toward the' hydrometer 63 and make a metallic contact between the ends of the two wires 9| and 92.

The active length of the compensating thermostatic element II from th clamp I5 to the pivot I0 should be such that the change in lengthfdue to temperature, should be equal to the change in height of the hydrometer, due to the change in specific gravity, necessary to maintain the same relative humidity according to the following table;- which shows the specific gravity of calcium chloride solutions in equilibrium conditions of vapor pressure with that of the relative humidity of air at the same temperature.

Electric power is supplied to the motor 6I-by the positive wire 93 controlled by the switch 94, and by the negative wire 95, to the fan motor float lower in the tube 84, tilting the lever 68 so that the mercury in the tube of the switch 69 flows toward the hydrometer 63 and makes a metallic contact between the ends of the wires er ,motor' 34 by means of the positive wires 9| and 92 and the negative wire 99, thereby moving the damper motor lever around the pivot 36 to move the bar 31 with the pivots 38 and to move the damper arm 39 to open the damper 26 and to close the damper 29 by means of the bar 3| and the pivots 32.

Under conditions of comparatively high relative humidity and continuous or nearly continuous use, the apparatus will function with the waste solution flowing through the pipes 2|, I1, 84, 80 and.82, with the valve I8 closed and the valves I9 and 8| opened, and through the tube 64, with the current in the positive wire 93 broken by opening the switch I01, thereby stopping the motor 6I, the fan 00 and the pump impeller 54.

In order to prevent the relative humidity from going below some predetermined point, means is provided by the spray I00, supplied with water through the pipe IOI and controlled by the solenoid valve I02 for adding humidity to the air when passing through the space 28. The auxiliary mercury switch I03 is placed adjacent to the mercury switch 69 with, the contact end tilted upward so as to cause a lag in time be- I tween breaking the contact in one mercury switch before making a contact in the other mercury switch due to a rising or lowering of the hydrometer 63 and the consequent tilting of the lever arm 68 in either direction. The solenoid valve I02 is normally closed and is opened when supplied with electric current through the positive'wires I04 and I05 and the negative wire I06, when th hydrometer 63 rises sufliciently to cause the mercury in the tube of the switch I03 to make a metallic contact between the ends of the wires I04 and I05. On a rising relative humidity above the predetermined point, the hydrometer 63 floats lower in the tube 64, the mercury in the tube of the auxiliary switch I03 flows toward the hydrometer 63 and breaks the contact between the ends of the wires I04 and I05,

' thereby breaking the circuit through the positive wires I04 and I05 and the negative wire I06,

closing the solenoid valve I02 and shutting off the water in the pipe IOI to the spray I00 to stop the increase in the relative humidity. The combination of these two means for decreasing and increasing relative humidity and the two mercury switches for controlling the action of both means provides for a very close control of rela- 23 by the positive wire 96, controlled by the from the ends of the wires 9| and 92 with the damper 26 closing and the damper 29 opening due to the tension of the spring 33.

, .On a rising relative humidity of the air entering the inlet 86, the hydrometer 63 begins to tive humidity.

It is to be understood that minor changes can be made inthe details of the invention in order to adapt it to practical use, including varying the' vapor pressure substantially in equilibrium with that of the. air being conditioned, determining the density of said solution and controlling the rate of dehydration of the air in accordance with the density, and compensating the control due to density according to the temperature of the air of the enclosure.

2 A method of conditioning air of an en closure to maintain a substantially constant relative humidity within a relatively wide dry bulb temperature range, comprising the steps of chemically dehydrating the air of said enclosure to form a waste hygroscopic solution having-a vapor pressure substantially in equilibrium with that of the air being conditioned, and regulating the rate of dehydration of the air through the joint control of solution density and temperature of the air of the enclosure.

3. In humidity control apparatus for chemically dehydrating the air of an enclosure, comprising a source of hygroscopic-solution, having had contact with the air being conditioned and having a vapor pressure in equilibrium condition with that of such air, a hydrometric element actuated by the density of said solution, a compensating thermostatic element actuated by the temperature of the air being conditioned and operatively associated with said hygroscopic element, and means under the control of said elements for regulating the humidity of the air being conditioned.

4. In an apparatus for conditioning air, a control for regulating relative humidity at variable temperatures comprising a source of hygroscopic solution having had contact with the air being conditioned and having a vapor pressure in equilibrium condition with that of such air, a hydrometric element actuated by the density of' said solution, thermostatic means actuated by the temperature of the 'air being conditioned,

and operative connections between said elements whereby the efiective action of said hydrometric element'is altered, and means under the control of the effective action of said hydrometric element for regulating the relative humidity of the air being conditioned.

HERAM JOSEPH KAUFMAN. 

